You may or may not be familiar with tmux, a powerful terminal multiplexer that lets you switch between multiple terminal emulators with configurable panes and windows, as well as detach processes and keep them running in the background. Whether you’re new to the idea of multiplexing, or switching from something like screen, Nate Dickson has an e-book to help you out: Painless Tmux.

This book is designed to help you get comfortable with tmux incrementally, helping you build up the kind of skill you need to fully utilize panes, windows, sessions and all the other power features of tmux.

The book is published through Leanpub, meaning free updates and flexible pricing. The suggested price is $9.99, but Nate has offered 10 20 codes for BrettTerpstra.com readers. Bonus: winners also receive a free copy of Painless Vim, which I covered a while back.

Update: due to the fantastic response, Nate has upped the giveaway to 20 copies!

To register for codes, just enter a name and email address below. 20 winners will be chosen randomly by the Giveaway Robot (Killotron 7800), and your email is used only for notification (Killotron incinerates them after the giveaway). Winners will receive codes for both Painless Tmux and Painless Vim (value $19.99 US). The drawing ends on Tuesday, June 9th, at 12PM CST. This drawing is open to all readers.

Sorry, this giveaway has ended.